Data security is the practice of keeping data protected from corruption and unauthorized access. The focus behind data security is to ensure privacy while protecting personal or corporate data. Data security has been one of the key areas of focus in the information technology (IT) industry.
Various data security methods include disk encryption, hardware based mechanisms, backups, data masking, and data erasure. Disk Encryption is the practice of encrypting data on a hard disk drive and may be implemented in software or hardware. Hardware based mechanisms, such as physical locks, can physically prevent read and write access to data and hence offer very strong protection against tampering and unauthorized access. Backups are used to ensure data which is lost can be recovered. Data masking of structured data is the process of obscuring (masking) specific data within a database table or cell to ensure that data security is maintained and sensitive information is not exposed to unauthorized personnel. This may include masking the data from users (for example, so banking customer representatives can only see the last four digits of a customer's account number), developers (who need real production data to test new software releases but should not be able to see sensitive financial data), outsourcing vendors, etc. Data erasure is a method of software-based overwriting that completely destroys all electronic data residing on a hard drive or other digital media to ensure that no sensitive data is leaked when the hard drive is retired or reused. Most of the algorithms at storage and retrieval impact the performance of the system since encryption and decryption increase computing overhead.